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05:04
Determining the Mechanical Strength of Ultra-Fine-Grained Metals
Published on: November 22, 2021
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Coarse graining and localized plasticity between sliding nanocrystalline metals
Pedro A Romero1, Tommi T Järvi1, Nils Beckmann2
1Fraunhofer Institute for Mechanics of Materials IWM, MicroTribology Center, Wöhlerstraße 11, 79108 Freiburg, Germany.
Physical Review Letters
|August 2, 2014
Summary
Nanocrystalline metals behave differently under sliding. Grains coarsen and rotate to optimize slip, leading to localized nanoshear bands instead of refinement.
Area of Science:
- Materials Science
- Tribology
- Nanotechnology
Background:
- Tribological shearing of polycrystalline metals usually refines grains.
- Nanocrystalline metals present a distinct case in tribological studies.
Purpose of the Study:
- To investigate the unique tribological behavior of nanocrystalline metals.
- To elucidate the mechanisms of plastic deformation at the sliding interface of nanocrystalline materials.
Main Methods:
- Large-scale atomistic simulations were employed.
- Analysis of grain self-organization, lattice rotation, and deformation localization.
Main Results:
- Nanocrystalline grains undergo self-organization via coarsening and lattice rotation during sliding.
- Optimal plastic slip orientation is established, leading to localized nanoshear bands.
- Deformation is confined to nanoshear bands aligned with the shearing direction, originating from defects.
Conclusions:
- Nanocrystalline metals exhibit grain coarsening and lattice rotation, not refinement, under tribological shearing.
- Plastic deformation localizes into nanoshear bands in nanocrystalline materials.
- Understanding these mechanisms is crucial for designing advanced materials for tribological applications.
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